1. Field of the Invention
The present invention relates to an inexpensive manufacturing method of long-lasting phosphor ceramics to be used in escape route signs and the like, and a sintered long-lasting phosphor having a light body color obtainable by the above manufacturing method.
2. Description of Related Art
The demand for a long-lasting phosphor to be used in escape route signs and the like has been increasing as its applications expand, since an MAl2O4:Eu,RE type long-lasting phosphor in which M is an alkaline earth element and RE is a rare earth element other than Eu was discovered by Nemoto & Co., Ltd. in 1993 (see, for example, Patent Document 1 indicated below). However, because of expensive materials and relatively high production cost, products of the phosphor are expensive, and accordingly, wide spread use of the phosphor has not yet been realized sufficiently. In addition, the phosphor is accompanied with another problem that due to a yellowish body color, it cannot be readily applied to signs required to have a white background.
Patent Document 1: Japanese Patent No. 2543825